1. Function: digital display with power, detachable, welding-free, with anti-reverse connection protection, can charge 21 18650 flat-head batteries, when the built-in battery can be used as a power bank, the normal version requires a charging cable, wireless fast charging The version does not require a charging cable and can be charged quickly. 2. Hand-made DIY mobile power kit, self-configured mobile power, larger battery capacity and more durable, can better solve your charging problem. 3. Suitable for people with greater charging needs, equipped with 3 charging interface types, for Micro, for Apple,for Type-C can charge the charging box. 4. With power display, let you know the remaining power anytime and anywhere, and better charge your mobile phone or other devices. 5. Comes with a lanyard, which is more convenient to carry, allowing you to take it wherever you go. Model: T21 series with light Battery: 18650 type flat head battery x 21 (free welding) Size: Thickness 62mm Width 84mm Length 170mm (internal dimensions remove a spring: thickness 55mm width 74mm length 129mm) Parameter : T21 with light: output/input maximum power: 5V-2.1A Precautions: 1. The battery cannot be used if its outer skin is . 2. Pointed batteries cannot be used, only flat batteries can be used. 3. The positive and negative poles need to be placed and used correctly. 4. Do not use or store in a high temperature environment. Colour:black Material: ABS Package Contents: 3x 18650 Power Bank Case(Batteries not included)